The invention relates to a process for carrying out an automated clutch actuation.
The German Reference DE 197 00 325 A1 shows a process for actuating a drive arrangement of a motor vehicle. The drive arrangement comprises a drive engine, a transmission, a clutch and a control unit. The clutch is disposed in the force flow between the drive engine and the transmission and can be moved in and out by means of the control unit.
After setting the driving speed (for example, by means of the gas pedal), the driving speed is adjusted by the control unit by means of the power setting element (throttle flap or injection pump). If this driving speed remains constant over a specific period, the clutch is opened to save fuel and the drive engine is adjusted back to idle speed. If, at this stage following this drive mode phase with opened clutch, the driving speed falls below a specific driving speed-dependent threshold value, the clutch is closed again.
The German Reference DE 42 13 589 A1 discloses a process to carry out an automated clutch actuation of a motor vehicle, in which process the automated clutch actuation is not performed until after a time delay, whereby its duration of time depends on the transmission ratio of the transmission and on the speed of the motor vehicle.
The object of the invention is to design a generic process more reliably and more comfortably.
It is an advantage of the invention that the variables, from which a dangerous situation in time or its termination can be concluded with a certain probability, are sensed so that the clutch can be moved into an operating position (opened or closed), which makes it possible to carry out faster the subsequent wish of the driver—such as an acceleration request or a braking request.
It is another advantage of the design that fuel is saved when a decrease in speed is desired.
It is a further advantage of the design of the process that the motor vehicle driver obtains feedback concerning which deflection or at which angle of the gas pedal the clutch changes the operating position. Thus, in the case of motor vehicle drivers, who are uncertain about the operating position of the clutch, and who want to achieve with certainty a specific operating position of the clutch, it is prevented in an advantageous manner that these motor vehicle drivers have to deflect the gas pedal to the maximum degree into one of the two possible directions. Thus, besides the subjective feeling of greater certainty, the advantages with respect to fuel consumption and driving safety are obtained.
Is it another advantage of the invention that braking, such as full braking in a dangerous situation, can be carried out without the brake system having to generate an additional braking torque in order to decelerate the output shaft of the drive engine.
The present invention involves a process wherein in the unpowered drive mode on a downgrade the clutch is closed in order to utilize the drag torque of the drive engine to decelerate the motor vehicle.
Another advantage of the invention is that the motor vehicle can also be accelerated, when the gas pedal is in a position that corresponds to the momentary speed of the motor vehicle. This situation that a relatively high rate of change of the gas pedal is detected, and that the motor vehicle exhibits, nevertheless, a speed that corresponds to the position of the gas pedal, can occur, for example, in a process for operating a drive arrangement in a motor vehicle, in which a tolerance range is provided for the angle of the gas pedal within which the unpowered operating phase does not end.